The punched hole on the curved face is always the rub of the stamping process. Taking the fixed block of the water heater container as an example, the short working life issue of the punching die was analyzed. The structure of the die used in the manufacturing process was studied. The cause affecting the working life of the punch was found. By the structure features of the fixed block of the water heater container, the die of the cutoff and the punched hole was optimized. Judging from the performance in the manufacturing process, this die can not only improve the service life of the punch, but also advance the work piece quality.